A more thorough explanation:

Definition: A mole is a person who has been a member of an organization for a long time and uses their position to gain access to and betray confidential information.

Example: A spy who works for a foreign government and infiltrates a company or government agency to steal secrets is a classic example of a mole. They may work for years to gain the trust of their colleagues and superiors, all the while secretly passing information to their handlers.

Explanation: Moles are often difficult to detect because they appear to be loyal members of the organization they are betraying. They may have access to sensitive information and use their position to gather intelligence or sabotage operations. The example of a spy working for a foreign government illustrates how a mole can be a serious threat to national security or a company's competitiveness.